One of the semiconductor devices is a nonvolatile memory. For example, there is known a nonvolatile memory that includes, as a memory transistor, a MOS (Metal Oxide Semiconductor) type field effect transistor storing information by accumulating charges (hot carriers) in the sidewall insulating film of a gate electrode sidewall.
For such a nonvolatile memory, there is known a technique of increasing the thickness of the sidewall insulating film of a transistor included in a circuit section in the periphery of a memory section including a memory transistor so as to reduce the injection efficiency of hot carriers of the former transistor.
See, for example, US Patent Application Publication No. 2008/0062745, Japanese Laid-open Patent Publication No. 2008-244097, and Japanese Laid-open Patent Publication No. 09-252059.
In a nonvolatile memory provided with a memory transistor group storing information by accumulating hot carriers in a sidewall insulating film, the programming speed of the entire nonvolatile memory depends on the programming speed of the individual memory transistor. If the programming speed of the individual memory transistor is not sufficient, then depending on the capacitance of a nonvolatile memory, a predetermined programming might not be able to be performed within a time period allowed on a system including the nonvolatile memory.